This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. A number of studies have demonstrated brain structure abnormalities in patients with schizophrenia, as well as in patients with comorbid cannabis abuse. This study is designed to answer the following questions: (1) does cannabis use impact the integrity or volume of brain white matter in the whole brain or in specific parts of the brain in adolescents with schizophrenia or in healthy controls? (2) do the findings from the magnetic resonance imaging studies correlate with neurocognitive findings or clinical symptoms?